Optimization of a Tracking-Based Approach for Calculating Energy Expenditure and Aerobic-Anaerobic Supplies During Intermittent Running: Improved Simulation of Oxygen Uptake Within the Metabolic Power Model.

In intermittent sports, tracking technologies are commonly used to monitor external and internal loads. The metabolic power model solely uses speed and acceleration data to simulate metabolic power, oxygen uptake, energy expenditure, and aerobic-anaerobic supplies. This study aimed to improve the simulation of oxygen uptake within the metabolic power model, thereby increasing its validity to estimate metabolic loads during intermittent running. Twelve male athletes (24 ± 3 years) performed different intermittent running-based exercises. These data were previously collected and used for secondary analysis within this study. The simulation of oxygen uptake was optimized by different approaches: (i) formerly detected bias (Offset model), (ii) data-driven modeling using differential evolution (Mongin model), and (iii) correction of the aerobic supply calculation. The simulations were compared to the measured oxygen uptake via a portable respiratory gas analyzer and the resulting metabolic loads to those derived by the established 3-component model. For statistical analysis, one-way repeated measures ANOVA or Friedman test with corresponding effect sizes were applied. Overall, the Mongin model demonstrated the best predictive accuracy (MAE = 4.99 ± 1.12 mL/min/kg) compared to measured oxygen uptake and, combined with the corrected calculation, total energy expenditure and aerobic supply did not significantly differ to the standard (p ≥ 0.056; trivial to large effect sizes). In conclusion, our optimizations reduce discrepancies of the tracking-based metabolic power model regarding total energy expenditure and aerobic supply compared to the established 3-component model.